Predictive Value of Proteinuria at the Time of IUGR Diagnosis for the Development of Preeclampsia or Gestational Hypertension

Intrauterine growth restriction (IUGR) is a major cause of perinatal morbidity and mortality, primarily resulting from uteroplacental insufficiency and maternal vascular dysfunction. Although proteinuria is traditionally a diagnostic criterion for preeclampsia, it may also have predictive value in normotensive pregnancies complicated by IUGR. This study aimed to evaluate whether proteinuria detected at the time of IUGR diagnosis in normotensive pregnancies predicts subsequent development of preeclampsia or gestational hypertension (PE/GHT). This retrospective cohort study included 180 women diagnosed with IUGR between 24–32 weeks of gestation at a tertiary perinatal center. Women with chronic hypertension, renal disease, diabetes, or multiple gestation were excluded. Proteinuria was assessed by either 24-hour urine collection (n = 106) or spot urine protein/creatinine (Pr/Cr) ratio (n = 74). Proteinuria was defined as ≥300 mg/day or Pr/Cr ≥0.30. The primary outcome was development of PE/GHT, analyzed using receiver operating characteristic (ROC) curves. In the 24-hour urine group, 68.8% of proteinuria-positive women and 16.2% without proteinuria developed PE/GHT (p < 0.001; AUC = 0.82, optimal cut-off 319.6 mg/day). In the spot Pr/Cr group, 75.0% of proteinuria-positive and 17.6% of proteinuria-negative women developed PE/GHT (p < 0.001; AUC = 0.89, cut-off 0.30). Proteinuria-positive women were approximately 4–5 times more likely to develop PE/GHT. Proteinuria detected at IUGR diagnosis—whether measured by 24-hour urine or spot Pr/Cr ratio—is a strong predictor of later hypertensive disorders. The spot Pr/Cr ratio provides comparable predictive accuracy and represents a practical, rapid screening method for early risk assessment in normotensive IUGR pregnancies.